With the rapid development of information technology, the use of computing devices, in particular, mobile computing devices, such as notebook computer, mobile phone and tablet device, becomes more and more popular, and the requirement to display quality of a display unit in the computing device becomes more and more critical. When the computing device displays images on the display unit, the refresh frequency of the display unit plays a key role in the stability of the images. Especially for the display of dynamic sequential images, the lower the refresh frequency is, the more serious the image blinking and dithering will be, and the more easily eye strain will grow. On the contrary, the higher the refresh frequency is, the more computing resources are occupied, and the more energy is consumed. A higher refresh frequency raises a higher requirement on the performance of the computing device. The maximum refresh frequency available for the display unit is generally limited by hardware and software of computing device, for example, bandwidth, and resolution of the image to be displayed.
For a mobile computing device, for example, a mobile phone, processes of controlling image display on the display unit may generally include image rendering, image composing and image displaying. For example, when a desktop program runs in the mobile phone to display a desktop interface on a screen of a display unit of the mobile phone and a video player runs in the mobile phone to display a video on the screen, a processor contained in the mobile phone may render images of the respective programs, compose the rendered images into a display frame, and output the display frame to the display unit to display it on the screen. The refresh frequency of the display unit is not well controlled in the related art.